In the manufacturing process for making glass, raw materials including sand, lime, soda ash and other ingredients are fed into a furnace, sometimes called a glass tank. The raw materials are subjected to temperature above about 2,800° F. (approximately 1538° C.) in the glass furnace which causes the raw materials to melt and thereby form a molten bed of glass that exits the glass furnace for further downstream processing into glass products.
The most common way of heating the glass furnace is through the combustion of a hydrocarbon fuel source, such as natural gas or oil. The hydrocarbon fuel is mixed with combustion air inside the furnace and combusted to thereby transfer the combustion heat energy to the raw materials and glass melt prior to exiting the furnace.
In order to improve the thermal efficiency of the combustion process, the combustion air used to combust the fuel is preheated by means of regenerator structures. More specifically, a supply of combustion air is preheated in a honeycombed pack of checker bricks contained within the interior of the regenerator structure. More specifically, fresh combustion air is drawn up through the pack of heated checker bricks in the regenerator structure and preheated by means of heat transfer. The pre-heated combustion air may then be mixed with the fuel, combusted. Waste combustion gas exits the glass furnace and passes through a second regenerator structure. As the waste gasses pass through the second regenerator the checkers in the pack are heated by means of heat transferred from the waste gas. After a predetermined time has elapsed (e.g., after about 15-30 minutes), the process cycle is reversed so that the checker bricks in one of the regenerator structures that were being heated by heat transfer with the waste gas are then used to preheat the fresh combustion air while the checker bricks in the other regenerator structures that were used to preheat the combustion air are then re-heated by heat transfer with the waste combustion gas. See in this regard, U.S. Pat. No. 3,326,541 (the entire content of which is expressly incorporated hereinto by reference).
The current process for building glass regenerator structures is very labor intensive taking many weeks as it requires the placement of hundreds of thousands of refractory bricks to be individually coated with mortar and placed. As is well known in the glass making industry, the mortar joints associated with the walls of the regenerator structure are the weakest part of the structure and are consequently more readily susceptible to degradation by the corrosive hot gasses passing through the regenerator. As the brick joints begin to erode, the walls forming the regenerator structure face increased attack as the corrosive gasses begin to condense and dissolve the refractory materials of the walls thereby weakening the structure. As the structure becomes weakened, the glass furnace itself may become compromised and fail which could then require a complete shut down and rebuilding operation.
It can be appreciated therefore, that if the regenerator structure (e.g., the regenerator walls, crown and riders) could be fabricated from larger refractory blocks, then fewer mortar joints would ensue thereby prolonging the regenerator structure's useful life and minimizing down time due to rebuilding. The embodiments disclosed herein therefore provide such needs as monolithic crown and rider arches are now provided that can be assembled during construction or refurbishment of glass furnace regenerator structures.